I rode DB many times, all over Germany and from Düsseldorf to Cologne weekly for months. Luckily, never had an issue. By far my worst experience has been Trenitalia. I lost a couple of connections during the same vacation because the train was late and in both opportunities no one could tell me what to do, let alone give me a refund. In one trip the teller while exhaling cigarette smoke on my face shrugged then suggested I took a bus from Campiglia to Piombino, which ended up been one of the scariest rides of my life (I have crossed the Andes in South America by speeding buses racing each other with 200 ft exposed cliff drops on the side, so I’m not strange to scary rides)

When was that? DB has gotten much worse in the past ~5 years